Fix deprecated issue & Support array result

[ningyougang]

• [x] Fix deprecated issue (fixed most parts, exist only 1 not solved, i created a issue: https://github.com/apache/openwhisk-cli/issues/518, we can open another separate pr to solve it)
• [x] Upgrade gradle to 6.9.1
• [x] Support array result https://github.com/apache/openwhisk-cli/pull/516#discussion_r950954594 concrete content: https://github.com/apache/openwhisk-cli/pull/516#issue-1246146973
• [x] Fix test case error

[ningyougang]

@style95 when build this pr in travis, it will execute its dependent openwhisk repo's test case, and it would be failed: https://app.travis-ci.com/github/apache/openwhisk-cli/builds/254265161, i copied the failed result as below

org.apache.openwhisk.core.cli.test.ApiGwCliTests > Cli Wsk api creation with path parameters with swagger should verify delete basepath/path FAILED
    org.scalatest.exceptions.TestFailedException: /home/travis/gopath/src/github.com/apache/openwhisk/bin/wsk -i --apihost 172.17.0.1 --apiversion v1 api create --auth 23bc46b1-71f6-4ed5-8c54-816aa4f8c502:123zO3xZCLrMN6v2BKK1dXYFpXlPkccOFqm12CdAsMgRU4VrNZ9lyGVCGuMDGIwP /CLI_APIGWTEST11_bp /path get CLI_APIGWTEST11_action --apiname CLI_APIGWTEST11 API Name

But strange thing is, the test case is successful when just build openwhisk repo's pr: https://github.com/apache/openwhisk/pull/5308 in travis ci

Have any idea? Already solved by below changes: https://github.com/apache/openwhisk-cli/pull/517#discussion_r950639632

[style95]

Have no idea, isn't there any openwhisk core version specified in this repo?

It seems not.

https://github.com/apache/openwhisk-cli/blob/92c251f5d3a873029ccd8d815409582301d1103d/.travis.yml#L59

[ningyougang]

Now there has only 1 test case failed

system.basic.WskCliActivationTests > Wsk poll should change the since time as it polls STANDARD_OUT

The test case startups a http server as proxy(http://localhost:$freePort) which points to https://172.17.0.1:443